Sound suppression hood assembly

ABSTRACT

A sound suppression hood assembly for use in reducing ambient noise levels generated by high intensity machinery, such as vibratory finishing machines or the like. The assembly includes a sound absorbing hood adapted to cover at least the upper portion of the sound-generating machine, and means for supporting the hood in pivotable relationship with respect to the machine. The support means is thus adapted for pivoting the hood about a horizontal axis, from a first, substantially horizontal position at which the hood overlies the covered machine portion, to a second or open position, at which the hood is displaced to a more vertical orientation, so as to enable access to the machine by an operator thereof.

United States Patent Gilbert et al.

SOUND SUPPRESSION HOOD ASSEMBLY Inventors: Anthony F. Gilbert, MorrisPlains;

John H. Munsey, Millington, both of NJ.

Coast Marine Associates, Inc., Dover, N .J

Filed: Feb. 11, 1974 Appl. No.: 441,518

Assignee:

US. Cl. 181/33 K, 51/268 Int. Cl E04b l/84 Field of Search 181/33 K;51/1 R, 262 R,

References Cited UNITED STATES PATENTS 3,785,452 l/1974 Scott 181/33 KPrimary Examiner-Richard B. Wilkinson Assistant Examiner-John F.Gonzales Attorney, Agent, or FirmStefan J. Klauber [57] ABSTRACT A soundsuppression hood assembly for use in reducing ambient noise levelsgenerated by high intensity machinery, such as vibratory finishingmachines or the like. The assembly includes a sound absorbing hoodadapted to cover at least the upper portion of the sound-generatingmachine, and means for supporting the hood in pivotable relationshipwith respect to the machine. The support means is thus adapted forpivoting the hood about a horizontal axis, from a first, substantiallyhorizontal position at which the hood overlies the covered machineportion, to a second or open position, at which the hood is displaced toa more vertical orientation, so as to enable access to the machine by anoperator thereof.

11 Claims, 3 Drawing Figures SOUND SUPPRESSION HOOD ASSEMBLY BACKGROUNDOF INVENTION This invention relates generally to sound suppressionapparatus and methodology, and more specifically relates to apparatusfor use in reducing ambient noise levels in the presence of high soundintensity machinery.

Within recent years it has become increasingly recognized that the highsound levels associated with operation of various types of machinery,are not only annoying and psychologically disruptive, but moreover arecapable of inflicting semi-permanent or permanent physical damage uponworkers and other personnel subjected to such sound particularly whereexposure to such environments is sustained over an extended period. Animportant consequence of such increasing awareness, is the promulgationby federal and state governments, of laws and regulations limiting thepermissible noise levels in environments where personnel are present.The United States Department of Labor, for example, has promulgated suchregulations with respect to manufacturing facilities coming within thepurview of the Walsh-Healey Public Contracts Act. Such regulations, forexample, limit the maximum acceptable noise exposure for an eight-hourshift to 90 dBA (decibels on the A scale of a standard sound levelmeter).

The present invention although not in any way limited thereto, hasparticular applicability for use with machinery such as vibratoryfinishing mills. Devices of this general type are very well known: atype, for example, may be seen in US. Pat. No. 3,708,918. Such machinesare primarily used for polishing or deburring small metal products, suchas hardware, e.g., nuts and bolts, or the like. The said work pieces arecommonly provided to a torroidally shaped processing chamber formingpart of the machine. This chamber may be accessible from the top of themachine in order that an operator may supply and remove work pieces tobe treated in the chamber or observe the operation. A carrier fluid iscommonly utilized in the chamber, and most often comprises a liquid withan abrasive material suspended therein, whereby the abrasive materialsmay act upon the work pieces to effect the deburring and/or polishingoperations. As is well known the said finishing operations may beconducted on either a batch or semicontinuous basis.

Machines of the foregoing and similar types (such as e.g., vibratoryfeeder bowls) or material handlers are well known to generateexceedingly high noise levels during operation thereof. In consequence aneed has long existed for effective means which can reduce the ambientnoise levels in the vicinity of such machinery. Certain devices have, inthe past, been proposed for use in these and in similar highnoise-producing environments, which devices, however, are relativelycumbersome and ineffective. For example, in US. Pat. No. 3,700,068, asound reduction device is set forth, which could presumably be used withmachinery of the type mentioned herein. The said sound reduction device,basically comprises a sheet plastic canopy, which is draped from anoverlying frame member about the machine, the noise production of whichis to be muffled. A principal difficulty with arrangements of this type,however, is that access to the said machinery is severely curtailed, andindeed is very cumbersome to obtain in the first instance; and yet suchaccess is a very necessary requirement, since the machine in questionmust be accessible both for observation purposes, and for removal orsupplying of work pieces, of grinding media, or so forth.

In accordance with the foregoing, it may be regarded as an object of thepresent invention, to provide a sound suppression device which is ofsimple and sturdy construction, and which is yet effective in greatlyreducing the ambient sound intensity of machinery associated therewith.

it is a further object of the present invention, to provide a soundsuppression assembly for use in reducing ambient noise levels in thepresence of high sound intensity machinery, which may be so associatedwith the said machinery that ready access to the machinery is enabledfor purposes of observation, maintenance, or furnishing of suppliesthereto.

It is a yet further object of the invention, to provide a soundsuppression assembly for use in reducing ambient noise levels of highsound intensity machinery such as vibratory finishing mills or the like,which may be readily displaced toward and away from the machine toenable access thereto, and which may further be associated withswitching means for inactivating the machinery where such access isprovided, thereby encouraging safe operation of the said machines, andpromoting proper use of the said assembly.

SUMMARY OF INVENTION Now in accordance with the present invention, theforegoing objects, and others as will become apparent in the course ofthe ensuing specification, are achieved in a sound suppression hoodassembly, which may be associated with high sound intensity machinery,as for example, vibratory finishing mills, feeder bowls, etc. to reducethe ambient noise levels in the vicinity of such machinery. The assemblyincludes a sound-absorbing hood, which is adapted to cover at least theupper portion of the machinery which is thereby muffled, together withmeans for pivotably supporting the hood with respect to the machine. Thepivot means is adapted for pivoting the said hood about a horizontalaxis from a first, substantially horizontal position at which the hoodoverlies but is in spaced relationship to the covered machine portion,to a second position at which the hood is displaced to a relatively morevertical orientation. This latter (or open) position enables access tothe machinery by an operator thereof.

The support means preferably includes a stand which engages theunderlying floor at one side of the machine, and a pivot assembly whichis secured to one side of the hood and about an axis of rotation at thestand. Spring or other force biasing means may be provided at the standand pivot assembly for facilitating displacement of the hood betweenopen and closed positions. The biasing means may thus comprise a rod,together with a spring-biased piston and cylinder assembly, theseelements extending between the stand and pivot assembly.

Where the sound suppression assembly is intended for use with apparatussuch as vibratory finishing mills, the hood may be configured to coverthe upper portion of the said mill when the hood is in its closedposition. Upon the hood being displaced to its open position, the accessopening to the treatment chamber of the mill may be readily entered byan operator from the top of the machine, as the hood is then swungcompletely clear of the top of the said machine.

The hood may be formed of thin plastic skins at its inner and outersurfaces, with an intervening core of sound-absorbant material such asfiberglass, or various synthetic or natural foams, such as polyurethanefoam, or so forth.

BRIEF DESCRIPTION OF'DRAWINGS The invention is diagrammaticallyillustrated, by way of example, in the drawings appended hereto, inwhich:

FIG. 1 is an elevational, partly schematic view of a sound suppressionhood assembly in accordance with the present invention, the saidassembly being shown in use with a vibratory finishing machine;

FIG. 2 is a detail cross-section through a portion of the hood of theFIG. 1 assembly; and- FIG. 3 is a longitudinal cross-sectional viewthrough the piston and cylinder portion of the assembly.

DESCRIPTION OF PREFERRED EMBODIMENT In FIG. 1 herein, an elevational,partly schematic view appears of a sound suppression hood assembly inaccordance with the present invention. Assembly 10 is representativelyshown in use with a vibratory finishing machine of the general typewhich has been heretofore been discussed in connection with thebackground portion of the instant specification. The said vibratoryfinishing machine 12 is thus seen to be emplaced at the floor 14 of aplant or other facility. Because machine 12 is conventional and not perse of the present invention, such machine is set forth in schematicfashion. In consequence of use of the machine 12 a very high soundintensity level would (in the absence of the invention) be encounteredin the surrounding portions of the facility.

Assembly 10 comprises a hood 16, and a hood supporting means 18 whichengages hood 16 at one side thereof and is, in turn, emplaced upon floor14. Supporting means 18 includes a stand 20 and a pivot assembly 22.Pivot assembly 22 is engaged with hood 16, as for example, by beingfastened to embedments 24 and 26 which are secured to the rim portion 28of the hood. Pivot assembly 22 is capable of rotation about an axis 30which is defined by a pin 32 passing through upright 34, and throughopenings in assembly 22. Assembly 22 may also be secured to hood 16 bymeans of a rod 36, which extends from assembly 22 to an embedment 38.Embedment 38 is fastened to the topmost portion 39 of hood 16, togetherwith an opposed embedment 40 on the inner side of the said hood. Rod 36serves a reinforcement function in securing the hood to assembly 22, andadds rigidity to the relatively bulky structure which includes hood l6and assembly 22.

The upright member 34 engages at its bottom end with a floor supportplate 42, which may be a flattened member of rectangular or other shape.A brace 44 extends between upright member 34 and plate 42. Additionalsuch braces may be present if a given installation so requires. A pairof upright members, one of which is seen at 46, include openings whichjournal a pin 50. The latter serves as an axis 48 for attachment of oneend of a rod 52, which rod end is provided with a transverse hole forreceipt of the said pin. Rod 52 is part .of a rod, piston and cylinderassembly, generally indicated at 54. This assembly includes at the upperend 56 of cylinder 58, a sleeve 60 which may be welded to the cylinder.A pin 62 passes through openings in assembly 22 and through'sleeve 60 soas to form a further axis 64 of rotation. I

Hood 16 is of generally bowl-shaped configuration, and as is best seenin FIG. 2, is comprised of a pair of opposed thin skins 59 and 61,formed for example of molded fiberglass or of a PVC or other typeplastic or so forth. A noise deadening core 66 is interposed betweenskins 59 and 61, and in a typical instance may comprise such materialsas fiberglass, balsa or other sound deadening material or varioussound-absorbing foams as, for example, of natural or artificial rubber,or of other elastomers such as polyurethanes. Typically the thickness ofskins 59 and 61 are about threesixteenths inch, with the interveningcore 66 being of the order of about one inch; but the actual thicknessesemployed will be a function of the particular applica-" tion of theinvention, and of the degree of sound attenuation sought to be achieved.6

The embedments 24, 26, 38 and 39, previously referred to, may comprisethin metal plates which are molded into skins 59 and 61 during formationof same. The embedments 24 and 26 may be provided-with aligned holes andintervening spaces may be present through core 66, so that threadedfasteners may be passed through the embedments and be used in engagingplate 21 of pivot assembly 22.

The specific configuration of hood 26 will be in accordance with theenvironments in which the invention is employed. In an instance such asthe present one, the schematically depicted vibratory finishing machine12, as has been previously mentioned, is often accessible from the upperor top end thereof whereat the treatment chamber 70 is located. Inaccordance with the principles of the present invention, it is thereforecontemplated that the hood 16 may be either emplaced in the closedposition shown in FIG. 1 in which its sound suppression function ismaximized or alternatively the hood may be pivoted upwardly as indicatedby arrow 73 to a more vertical position, at which access to theoperating machine may be readily achieved. This open position ispartially seen in shadow at 16. In an arrangement such as that of thistype, the open position is fully reached after rotation through an angleof about 60.

It will firstly be noted in the foregoing connection, that when hood 16is in its operative or soundsuppressing position as shown in FIG. 1, thehood, while surrounding the upper portions of machine 12, is actuallyspaced from the said machine. The objective of this arrangement is tominimize direct coupling of machine vibrations to the hood, whereby toassure maximization of the muffling properties of the device. It will befurther noted that the lateral rim 28 is substantially verticallyoriented, and actually extends to a point which is well below the uppercover 76 of machine 12. It is therefore apparent that theconfigurationused in FIG. 1 is such as to surround the access portion of the saidmachine which lies beneath cover 76. The effectiveness of assembly 10 inrendering sound levels is attested to by typical instances in whichambient sound levels generated by machines such as at 12, were reducedfrom l03 dBA to dBA by use of the present invention.

Hood 16 is preferably provided with handle means generally indicated at72, which are secured to rim 28 at a position opposed to stand 20.Embedments, as indicated at 78 and 80 may be secured e.g., by fastenersor by molding, etc. to hood 16 to enable attachment of handle 72.

During operation of assembly 10, the operator may, as desired, grasphandle means 72 to raise the hood to an upper more vertical position tothereby gain access to the machine. In order to enable this operation tobe readily carried out, rod, piston and cylinder assembly 54 provides aforce-biasing function. In particular it is seen that the said assembly54 extends between support plate 42 and the pin 62 at pivot assembly 22,and that axes of rotation 48 and 64 are provided at both ends. As bestseen in the longitudinal cross-sectional view of FIG. 3, cylinder 58 isclosed at its upper end 56. A piston 82 is mounted for movement withincylinder 58, and includes a packing ring 84 of Teflonor the like. Therod 52 secured to piston 82, extends from the cylinder as previouslyindicated, and carries a stopping shoulder 86, which is fixedly securedthereabout.

In the embodiment illustrated, the biasing force is provided by means ofa spring 88 which is present in the space between the underside ofpiston 82 and a cylinder closing member 90 which slidingly receives rod52. With hood 16 in the closed position shown in FIG. 1, the shoulder 86will rest against the internal side of member 90, whereby spring 88 iscompressed to its maximum, and as the hood is raised i.e., pivoted aboutaxis 30 the degree of spring compression is reduced, as is the reactionforce at member 90 due to the spring. This in turn gradually reduces thecounterclockwise torque about axis 30. At the fully open position 16'(FIG. 1), piston 82 is at or somewhat below inner face 92 of cylinderportion 56. Spring 88 is at all times under some degree of compression.The spring constant is selected in relationship to the geometry (andweight distribution) of assembly so that hood 16 is approximatelycounterbalanced at all positions except that within about a 5 arc of theclosed (i.e., horizontal) position the geometry (and weightdistribution) is such that the clockwise torque about axis 30 (in thesense of the Figures) exceeds the counterclockwise torque, so that hood16 will not inadvertently be left in a partially open position. Theclockwise torque about axis 30 is, of course, principally determined bythe weight of hood 16 and by the distance of the center of gravity ofthe hood from axis 30 at a given hood position.

It should be understood that the spring biasing means illustrated foruse with the present pivoted assembly 22 may be replaced by otherforce-biasing means as, for example, by pneumatically-actuated rod,piston and cylinder arrangements. It should also be evident that inthese latter instances a completely automatic operation can be providedfor opening and closing the hood which is to say that the entire forcefor pivoting the said hood among its positions may be provided by thepneumatic piston and cylinder arrangement.

According to a further aspect of the present invention a limit switch,schematically suggested at 94 may serve to enable operation of machine12. In particular, assuming by way of example, that switch 94 is anormally-off microswitch, which in turn actuates power relays or thelike to enable power to machine 12, it will be evident that the saidmachine may only operate when hood 16 is fully lowered to its FIG. 1position at which point contact with the said microswitch is made. Thisarrangement not only assures that machine 12 will only be operated whenfull advantage is being taken of the soundabsorbing properties ofassembly 10, but moreover serves a safety function. In particular,assuming that access to operating components of the machine may not behad unless the hood is displaced to a more vertical position, it will beevident that any attempt to reach the operating portions or the machinewill necessitate upward pivoting of the hood, which, in turn, willdisable operation of the said machine.

While the present invention has been particularly set forth in terms ofa specific embodiment thereof, it will be understood that numerousvariations upon the invention are now enabled to those skilled in theart, which variations yet reside within the scope of the presentteaching. The hood 16, for example, is in no way limited to acylindrical or spherical geometry, but may be of generally rectangularor other shape when the requirements of the machine with which the hoodis employed, so demand; provided only that the concave portion of suchhood are appropriately directed for interaction with the said machine.Accordingly the invention is to be broadly construed and limited only bythe scope and spirit of the claims now appended hereto.

We claim:

1. A sound suppression hood assembly for use in reducing ambient noiselevels in the presence of high sound intensity machinery, comprising incombination:

a sound-absorbing hood adapted to cover at least the upper portion of afloor-supported high sound intensity machine;

stand means including an upright and means supporting said upright withrespect to said floor, for pivotably supporting said hood with respectto said machine; a pivot assembly being secured between one side of saidhood and said stand means; and force biasing means being provided atsaid stand means and pivot assembly, for counterbalancing said hoodweight to facilitate pivoting of said hood back and forth between afirst substantially horizontal position at which said hood overlies butis in spaced relationship to said covered machine portion, and a second,open position at which said hood is dis placed to a more verticalorientation, to enable access to said machine by an operator thereof,said upright and said support means for said upright both beingpositionable to one side of said machine whereby access to said machineis substantially unimpaired when said hood is in said open position, andsaid stand means being spaceable substantially in its entirety from saidmachine, whereby direct coupling of machine vibrations to said hood isminimized.

2. Apparatus in accordance with claim 1, wherein said hood comprisesopposed thin skins and an intervening sound-absorbing core.

3. Apparatus in accordance with claim 1, wherein said biasing meanscomprises a rod, piston and cylinder assembly, extending between saidstand means and said pivot assembly.

4. Apparatus in accordance with claim 5, wherein said piston is biasedby a spring.

5. Apparatus in accordance with claim 1, further including handle meanssecured to said cover and projecting externally therefrom, for graspingby said operator, whereby to enable operator-activated movement of saidcover between said first and second positions.

6. Apparatus in accordance with claim 1, wherein said hood is ofgenerally bowl-shaped configuration, and comprises opposed plastic skinsand an intervening noise-absorbing core.

7. In combination with a floor-supported vibratory finishing machine ofthe type including a treatment chamber and chamber access means at thetop of said machine; a sound suppression hood assembly, comprising incombination:

a sound absorbing hood configured to surround at least the upper portionof said vibratory finishing machine including the said chamber accessmeans; and

means for supporting said hood in pivotable relationship with respect tothe upper portion of said machine, said means being adapted for pivotingsaid hood about a horizontal axis from a substantially derlying floor atone side of said finishing machine; and

a pivot assembly secured to one side of said hood and to an axis ofrotation at said pivot assembly.

9. Apparatus in accordance with claim 8, further insound intensitymachinery, comprising in combination:

a sound-absorbing hood adapted to cover at least the upper portion of afloor-supported high sound intensity machine;

means for pivotably supporting said hood with respect to said machine,said means being adapted for pivoting said hood from a firstsubstantially hor izontal position at which said hood overlies but is inspaced relationship to said covered machine portion, to a second, openposition at which said hood is displaced to a more vertical orientation,to enable access to said machinery by an operator thereof; and

switching means activated by the pivotable movement of said hood, todisable electrical power to said high sound intensity machine when saidhood is pivoted upwardly from said first position, whereby to enablesafe access to said machine and to assure proper utilization of saidhood.

1. A sound suppression hood assembly for use in reducing ambient noiselevels in the presence of high sound intensity machinery, comprising incombination: a sound-absorbing hood adapted to cover at Least the upperportion of a floor-supported high sound intensity machine; stand meansincluding an upright and means supporting said upright with respect tosaid floor, for pivotably supporting said hood with respect to saidmachine; a pivot assembly being secured between one side of said hoodand said stand means; and force biasing means being provided at saidstand means and pivot assembly, for counterbalancing said hood weight tofacilitate pivoting of said hood back and forth between a firstsubstantially horizontal position at which said hood overlies but is inspaced relationship to said covered machine portion, and a second, openposition at which said hood is displaced to a more vertical orientation,to enable access to said machine by an operator thereof, said uprightand said support means for said upright both being positionable to oneside of said machine whereby access to said machine is substantiallyunimpaired when said hood is in said open position, and said stand meansbeing spaceable substantially in its entirety from said machine, wherebydirect coupling of machine vibrations to said hood is minimized. 2.Apparatus in accordance with claim 1, wherein said hood comprisesopposed thin skins and an intervening sound-absorbing core.
 3. Apparatusin accordance with claim 1, wherein said biasing means comprises a rod,piston and cylinder assembly, extending between said stand means andsaid pivot assembly.
 4. Apparatus in accordance with claim 5, whereinsaid piston is biased by a spring.
 5. Apparatus in accordance with claim1, further including handle means secured to said cover and projectingexternally therefrom, for grasping by said operator, whereby to enableoperator-activated movement of said cover between said first and secondpositions.
 6. Apparatus in accordance with claim 1, wherein said hood isof generally bowl-shaped configuration, and comprises opposed plasticskins and an intervening noise-absorbing core.
 7. In combination with afloor-supported vibratory finishing machine of the type including atreatment chamber and chamber access means at the top of said machine; asound suppression hood assembly, comprising in combination: a soundabsorbing hood configured to surround at least the upper portion of saidvibratory finishing machine including the said chamber access means; andmeans for supporting said hood in pivotable relationship with respect tothe upper portion of said machine, said means being adapted for pivotingsaid hood about a horizontal axis from a substantially horizontalposition at which said hood overlies but is in spaced relationship tothe upper portion of said finishing machine, to a second, open positionat which said hood is displaced to a more vertical position, to enablean operator to utilize the said access means for said treatment chamber.8. Apparatus in accordance with claim 7, wherein said support meanscomprises a stand engaging the underlying floor at one side of saidfinishing machine; and a pivot assembly secured to one side of said hoodand to an axis of rotation at said pivot assembly.
 9. Apparatus inaccordance with claim 8, further including force biasing means at saidstand and pivot assembly, for facilitating displacement of said hoodbetween said first and second positions.
 10. Apparatus in accordancewith claim 9, wherein said cover is of generally bowl-shapedconfiguration, and comprises opposed thin plastic skins and anintervening sound absorbing core structure.
 11. A sound suppression hoodassembly for use in reducing ambient noise levels in the presence ofhigh sound intensity machinery, comprising in combination: asound-absorbing hood adapted to cover at least the upper portion of afloor-supported high sound intensity machine; means for pivotablysupporting said hood with respect to said machine, said means beingadapted for pivoting said hood from a first substantially horizontalposition at which said hood overlies but is in Spaced relationship tosaid covered machine portion, to a second, open position at which saidhood is displaced to a more vertical orientation, to enable access tosaid machinery by an operator thereof; and switching means activated bythe pivotable movement of said hood, to disable electrical power to saidhigh sound intensity machine when said hood is pivoted upwardly fromsaid first position, whereby to enable safe access to said machine andto assure proper utilization of said hood.